Phospholipids are naturally occurring nonionic surface active agents which are valuable in the field of foods, medicines and production of various materials. Phospholipids are mainly produced from biological materials, and the composition of the phospholipids is one of the elements which determine the quality of the material.
The factor which participates in the determination of the composition of phospholipids is unknown and no methods by which the composition of phospholipids is changed by genetic engineering process have been reported.